Relays are typically used to switch a variety of electrical loads ON and OFF by connecting and disconnecting the load from a power source, such as a DC power source. For example, a relay may switch an electronic ballast used in lighting applications ON and OFF. Relays may be manually or electronically switched, e.g., in response to a control signal.
When an electrical capacitive load powered by an AC power line is switched ON and OFF with a relay, it is desirable to switch the relay at or near a zero crossing of the AC line voltage to minimize the inrush current. If a relay is switched randomly or at points that are not in close proximity to the zero crossing points of the AC line voltage, the AC voltage may be significant, resulting in the delivery of high inrush current to a downstream electrical load. This high inrush current may damage the contacts of the relay and/or the electrical load, and may decrease the operating lifetime of such components.